%0 Journal Article %A Claude Farah %A Sue Downie %A Jessica Kermode %A Nathan Brown %A Kate Hardaker %A Gregory King %A Norbert Berend %A Cheryl Salome %T Ventilation heterogeneity is associated with asthma control in adults %D 2011 %J European Respiratory Journal %P p4019 %V 38 %N Suppl 55 %X Background: The clinical relevance of increased ventilation heterogeneity, a marker of small airways disease, in asthma is unclear. Ventilation heterogeneity is an independent determinant of airway hyperresponsiveness, improves with bronchodilators and inhaled corticosteroids (ICS), and worsens during exacerbations but its relationship to asthma control is unknown.Objective: To determine the association between ventilation heterogeneity and current asthma control before and after ICS treatment.Methods: Asthmatic subjects had the 5-item symptom-only asthma control questionnaire (ACQ5) and lung function measured at baseline and after 3 months of high dose ICS treatment. Ventilation heterogeneity was measured as Scond and Sacin by multiple breath nitrogen washout. Scond and Sacin represent ventilation heterogeneities in small airways where gas transport occurs mainly by convection or diffusion, respectively. Spearman correlations and paired t-tests were performed.Results: At baseline (n=110, 64 female), ACQ5 correlated with Scond (rs = 0.30, p=0.002) and Sacin (rs = 0.21, p=0.03). After treatment (n=55), the mean (SD) ACQ5 improved (1.31 (0.71) to 0.70 (0.77), p<0.0001), Scond improved (0.068 (0.035) to 0.053 (0.033) L-1, p<0.0001) but Sacin did not significantly change (0.147 (0.07) to 0.142 (0.06) L-1, p=0.28). The change in ACQ5 correlated with changes in Scond (rs = 0.34, p=0.02) and Sacin (rs = 0.33, p=0.01).Conclusions: Current asthma control is associated with markers of small airways disease. Improvements in ventilation heterogeneity with anti-inflammatory therapy are associated with improvements in symptoms. Sensitive measures of small airway function may be useful in monitoring therapy in asthma. %U